Ohio Rev. Code § 3307.76
A member of the state teachers retirement system participating in the STRS defined benefit plan shall, in computing years of total service, be given full credit for time served in the public employees retirement system under Chapter 145. of the Revised Code or in the school employees retirement system under Chapter 3309. of the Revised Code if the member purchases the credit in accordance with section 3307.70 of the Revised Code.
A member is ineligible to purchase credit described in this section if credit for the service may be obtained from the public employees retirement system or school employees retirement system or if the credit is for service that is used in the calculation of any retirement benefit that has been paid, is currently being paid, or is payable in the future to the member.
R.C. § 3307.76