N.D. Cent. Code § 16.1-12-06
When one individual has been nominated for the same office by more than one body of electors qualified to make nominations for public office, the nominee shall file with the secretary of state on or before the last day fixed by law for filing certificates of nomination for the office, a signed statement designating the political party the nominee desires to represent. The political party so designated must be the political party of one of the bodies of electors by whom the individual was nominated. In the absence of a timely written designation as provided by this section, the secretary of state shall place the individual's name with the name of the political party of the body of electors from which the individual's nomination was received first.
N.D.C.C. § 16.1-12-06