Ohio Rev. Code § 3319.21
Whenever a local director or member of a board of education votes for or participates in the making of a contract with a person as a teacher or instructor in a public school to whom he is related as father, brother, mother, or sister, or acts in any matter in which he is pecuniarily interested, such contract, or such act in such matter, is void.
This section does not apply where a director or a member of such board, being a shareholder of a corporation but not being an officer or director thereof, owns not in excess of five per cent of the stock of such corporation and the value of the stock so owned does not exceed five hundred dollars. If a stockholder desires to avail himself of the exception provided in this section, before entering upon such contract such person shall first file with the treasurer of the board an affidavit stating his exact status and connection with said corporation.
R.C. §3319.21