The commission, upon reasonable notice, shall decide in each application for certification as an exclusive bargaining representative the unit appropriate for the purpose of collective bargaining. In determining, modifying, or combining the bargaining unit, the commission shall consider the duties, skills, and working conditions of the symphony musicians; the history of collective bargaining by the symphony musicians and their bargaining representatives; the extent of organization among the symphony musicians; and the desire of the symphony musicians. The commission shall determine the bargaining representative by: (1) Comparison of signatures on organization bargaining authorization cards; or (2) conducting an election specifically therefor.