A petition for an election of an exclusive representative may be submitted to the Labor Commissioner by: an employee organization that demonstrates that at least 30% of the eligible employees in the bargaining unit support representation by an exclusive representative for collective bargaining; an employee, a group of employees, or an employee organization that demonstrates that at least 35% of the eligible employees in the bargaining unit certify that a majority of the eligible employees in the bargaining unit no longer support the current exclusive representative; or subject to paragraph (2) of this subsection, the Commission, demonstrating that one or more employee organizations have presented to it a claim, supported by substantial proof, to be certified as the exclusive representative. The Labor Commissioner may accept a petition from the Commission only if the Labor Commissioner finds, on investigation of the petition, that a valid question of representation exists. Elections shall be conducted by: the Labor Commissioner; and secret ballot. Each ballot shall contain: the name of each employee organization that submits a valid petition; the name of any other employee organization supported by a valid petition signed by more than 10% of the eligible employees in the bargaining unit; and an option for no representation. If none of the choices on the ballot receives a majority of the votes cast, the Labor Commissioner shall conduct a runoff election. In the runoff election, the ballot shall contain the two choices receiving the highest number of votes cast in the initial election. After the election, the Labor Commissioner shall certify the employee organization that received a majority of the votes cast as the exclusive representative. An employee organization may not be certified as an exclusive representative except as provided in this subtitle. Elections may not be conducted within 2 years after a valid election held under this section.