Ohio Rev. Code Ann. § 703.12

Each census enumerator, with the return of the census enumeration to the city auditor, shall return the book containing the list of the names and addresses, and shall certify with his affidavit that he has taken and returned the census accurately to the best of his knowledge and belief, and that such list contains the names of all persons so enumerated and no others. The auditor or any officer authorized to administer oaths may administer such oath or affirmation, and may take and certify such affidavit.