Ohio Revised Code Title XXIX. Crimes Procedure § 2945.15

When two or more persons are tried jointly, before any of the accused has gone into his defense the trial court may direct one or more of such accused to be discharged that he may be a witness for the state.

An accused person, when there is not sufficient evidence to put him upon his defense, may be discharged by the court, but if not so discharged, shall be entitled to the immediate verdict of the jury in his favor. Such order of discharge, in either case, is a bar to another prosecution for the same offense.