Ohio Rev. Code Ann. § 2941.1420
(A) Imposition of a mandatory indefinite prison term consisting of a minimum term of fifteen years and a maximum term of life imprisonment upon an offender pursuant to division (A)(3)(e)(iv) or (B)(2)(c) of section 2971.03 of the Revised Code is precluded unless the offender is convicted of or pleads guilty to attempted rape and unless the indictment, count in the indictment, or information charging the offense specifies that, had the offender completed the rape that was attempted, the offender would have been guilty of rape in violation of division (A)(1)(b) of section 2907.02 of the Revised Code, and any of the following apply:
(1) The offender previously has been convicted of or pleaded guilty to one of the following: