Ohio Rev. Code § 3319.12
Each board of education shall cause notice to be given annually not later than the first day of July to each teacher who holds a contract valid for the succeeding school year, as to the salary to be paid such teacher during such year. Such salary shall not be lower than the salary paid during the preceding school year unless such reduction is a part of a uniform plan affecting the entire district. This section does not prevent increases of salary after the board's annual notice has been given.
Except by mutual agreement of the parties thereto a teacher employed under a contract of employment in an administrative or supervisory position in a school district, or in any position provided for by section 3319.01 or 3319.02 of the Revised Code, shall not be transferred during the life of the teacher's contract to a position of lesser responsibility. No contract or supplemental contract for the employment of a teacher, whether for an administrative or supervisory position, a position provided for by sections 3319.01 and 3319.02 of the Revised Code, regular teaching duties, or additional duties, may be terminated or suspended by a board of education except pursuant to section 3311.82, 3319.02, or 3319.16 of the Revised Code, and the salaries and compensations prescribed by such contracts shall not be reduced by a board of education unless such reduction is a part of a uniform plan affecting the entire district. This section shall apply only to contracts entered into after August 18, 1969.
R.C. § 3319.12