Ohio Rev. Code § 511.13
No member of the board of township trustees or any officer or employee thereof shall be interested in any contract entered into by such board. No such person shall be individually liable to any contractor upon any contract made under sections 511.08 to 511.17, inclusive, of the Revised Code, nor shall he be liable to any person on any claims occasioned by any act or default of a contractor or anyone employed by him.
This section does not apply where such person is a shareholder of a corporation, but not an officer or director thereof, and owns not more than five per cent of the stock of such corporation, the value of which does not exceed five hundred dollars.
If a stockholder desires to avail himself of the exception provided in this section, he shall, before entering upon such contract, first file with the clerk of the board of county commissioners, an affidavit, stating his exact status and connection with the corporation.
R.C. § 511.13