Ohio Rev. Code § 2107.12: Contest of jurisdiction.

When a will is presented for probate or for a declaratory judgment of its validity pursuant to Chapter 5817. of the Revised Code, persons interested in its outcome may contest the jurisdiction of the court to entertain the application. Preceding a hearing of a contest as to jurisdiction, all parties named in such will as legatees, devisees, trustees, or executors shall have notice of the hearing in such manner as may be ordered by the court.

When that contest is made, the parties may call witnesses and shall be heard upon the question involved. The decision of the court as to its jurisdiction may be reviewed on error.