Ohio Rev. Code Ann. § 2151.38

Subject to sections 2151.353 and 2151.412 to 2151.421 of the Revised Code, and any other provision of law that specifies a different duration for a dispositional order, all dispositional orders made by the court under this chapter shall be temporary and shall continue for a period that is designated by the court in its order, until terminated or modified by the court or until the child attains twenty-one years of age.