(a) The labor relations agency shall investigate a petition if it is submitted in a manner prescribed by the labor relations agency and is

(1) by an employee or group of employees or an organization acting in their behalf alleging that 30 percent of the employees of a proposed bargaining unit

(A) want to be represented for collective bargaining by a labor or employee organization as exclusive representative, or

(B) assert that the organization which has been certified or is currently being recognized by the public employer as bargaining representative is no longer the representative of the majority of employees in the bargaining unit; or

(2) by the public employer alleging that one or more organizations have presented to it a claim to be recognized as a representative of a majority of employees in an appropriate unit.

(b) If the labor relations agency has reasonable cause to believe that a question of representation exists, it shall provide for an appropriate hearing upon due notice. If the labor relations agency finds that there is a question of representation, it shall direct an election by secret ballot to determine whether or by which organization the employees desire to be represented and shall certify the results of the election. Nothing in this section prohibits the waiving of hearings by stipulation for the purpose of a consent election in conformity with the regulations of the labor relations agency or an election in a bargaining unit agreed upon by the parties. The labor relations agency shall determine who is eligible to vote in an election and shall establish rules governing the election. In an election in which none of the choices on the ballot receives a majority of the votes cast, a runoff election shall be conducted, the ballot providing for selection between the two choices receiving the largest and the second largest number of valid votes cast in the election. If an organization receives the majority of the votes cast in the election it shall be certified by the labor relations agency as exclusive representative of all the employees in the bargaining unit.

(c) An election may not be held in a bargaining unit or in a subdivision of a bargaining unit if a valid election has been held within the preceding 12 months.

(d) Nothing in this chapter prohibits recognition of an organization as the exclusive representative by a public agency by mutual consent.

(e) An election may not be directed by the labor relations agency in a bargaining unit in which there is in force a valid collective bargaining agreement, except during a 90-day period preceding the expiration date. However, a collective bargaining agreement may not bar an election upon petition of persons in the bargaining unit but not parties to the agreement if more than three years have elapsed since the execution of the agreement or the last timely renewal, whichever was later.