Ohio Revised Code Title III. Counties § 319.35

From time to time the county auditor shall correct all clerical errors the auditor discovers in the tax lists and duplicates in the name of the person charged with taxes or assessments, the description of lands or other property, the valuation or assessment of property or when property exempt from taxation has been charged with tax, or in the amount of such taxes or assessment, and shall correct the valuations or assessments on the tax lists and duplicates agreeably to amended, supplementary, or final assessment certificates.  If the correction is made after a duplicate is delivered to the county treasurer, it shall be made on the margin of such list and duplicate without changing any name, description, or figure in the duplicate, as delivered, or in the original tax list, which shall always correspond exactly with each other.

For the purposes of this section and section 319.36 of the Revised Code, a clerical error is an error that can be corrected by the county auditor from the inspection or examination of documents in the county auditor's office or from the inspection or examination of documents that have been presented to the county auditor and have been recorded by the county recorder.  Except as otherwise provided by law, any error in the listing, valuation, assessment, or taxation of real property other than a clerical error constitutes a fundamental error and is subject to correction only by the county board of revision as provided by law.