Ohio Rev. Code § 3515.12
The court with which a petition to contest an election is filed may summon and compel the attendance of witnesses, including officers of such election, and compel the production of all ballot boxes, marking devices, lists, books, ballots, tally sheets, and other records, papers, documents, and materials which may be required at the hearing. The style and form of summons and subpoenas and the manner of service and the fees of officers and witnesses shall be the same as are provided in other cases, in so far as the nature of the proceedings admits. The court may require any election officer to answer any questions pertinent to the issue relating to the conduct of the election or the counting of the ballots and the making of the returns. Any witness who voted at the election may be required to answer touching his qualification as a voter and for whom he voted.
R.C. §3515.12