Section 1311 - Determination and certification of exclusive representative(a) Any employee organization seeking certification as exclusive representative in a designated appropriate bargaining unit shall file a petition with the Board. The petition must contain the uncoerced signatures of at least 30 percent of the employees within the designated appropriate bargaining unit. If the designated appropriate bargaining unit is sufficiently similar to the bargaining unit claimed to be appropriate in the petition filed pursuant to § 1310(a) of this title, such that the signatures submitted at that time represent 30 percent of the employees within the designated appropriate bargaining unit, those signatures shall be deemed sufficient for the purpose of this subsection. If the designated bargaining unit is not sufficiently similar to the bargaining unit claimed to be appropriate, the employee organization may continue to rely on the previously submitted uncoerced signatures of the employees who are in the designated bargaining unit and must supplement these signatures with uncoerced signatures of other employees within the designated appropriate bargaining unit, such that the signatures submitted represent at least 30 percent of the employees within the designated appropriate bargaining unit. No signature shall be considered valid if it was signed more than 12 months prior to the date on which the petition is filed.(b) Where an employee organization has been certified as the exclusive representative, a group of employees within the bargaining unit may file a petition with the Board for decertification of the exclusive bargaining representative. The petition must contain the uncoerced signatures of at least 30 percent of the employees within the bargaining unit and allege that the employee organization presently certified is no longer the choice of the majority of the employees in the bargaining unit. If a lawful collective bargaining agreement of no more than 3 years' duration is in effect, no petition shall be entertained unless filed not more than 180 days nor less than 120 days prior to the expiration of such agreement. A decertification petition also may be filed if more than 1 year has elapsed from the date of certification of an exclusive bargaining representative and no collective bargaining agreement has been executed, and the procedures for mediation and fact-finding have been invoked and completed as provided in this chapter. (c) If the Board determines that a petition is properly supported, timely filed and covers the designated appropriate bargaining unit, the Board shall cause an election of all eligible employees to be held within a reasonable time after the unit determination has been made, in accordance with procedures adopted by the Board, to determine if and by whom the employees wish to be represented. The election ballot shall contain, as choices to be made by the voter, the name of the petitioning employee organization and the certified employee organization, the name or names of any other employee organization showing written proof of at least 10 percent representation of the public employees within the designated appropriate bargaining unit, in accordance with rules and procedures adopted by the Board, and a choice that the public employee does not desire to be represented by any of the named employee organization(s).(d) The employee organization, if any, which receives the majority of the votes cast in an election shall be certified by the Board as the exclusive representative. In any election where there are more than 2 choices on the ballot and none of the choices receives a majority of the votes cast, a run-off election shall be conducted. The ballot in the run-off election shall contain the 2 choices on the original ballot that received the largest number of votes.(e) No election shall be held pursuant to this section within 12 months from the date of a preceding valid election.19 Del. C. 1953, §§ 1304-1307; 55 Del. Laws, c. 126; 65 Del. Laws, c. 499, §1; 69 Del. Laws, c. 466, §1.;