Ohio Rev. Code § 1331.13
If a court of record, or a judge thereof in vacation, in which is pending a civil or criminal action or proceeding brought or prosecuted by the attorney general or a prosecuting attorney for the violation of sections 1331.01 to 1331.14, inclusive, of the Revised Code, or an action or proceeding for a violation of a law, common or statute, against a conspiracy or combination in restraint of trade, so orders, no person shall be excused from attending, testifying, or producing books, papers, schedules, contracts, agreements, or other documents in obedience to the subpoena or order of such court or a commissioner, referee, or master appointed by such court to take testimony, or a notary public or other person authorized to take depositions, when the order made by such court or judge includes a witness whose deposition is being taken before such notary public or other officer, for the reason that the testimony or evidence required of him may tend to incriminate him or subject him to a penalty. No person shall be prosecuted or subjected to a penalty for or on account of a transaction, matter, or thing concerning which he may so testify or produce evidence, documentary or otherwise, before such court, person, or officer.
R.C. §1331.13