individual or labor organization acting in their behalf alleging that a substantial number of employees (i) wish to be represented for collective bargaining and that their employer declines to recognize their representative as the representative defined in section 9(a), or (ii) assert that the individual or labor organization, which has been certified or is being recognized by their employer as the bargaining representative, is no longer a representative as defined in section 9(a), the Board shall investigate such petition and if it has reasonable cause to believe that a question of representation affecting commerce exists shall provide for an appropriate hearing upon due notice. Such hearing may be conducted by an officer or employee of the regional office, who shall not make any recommendations with respect thereto. If the Board finds upon the record of such hearing that such a question of representation exists, it shall direct an election by secret ballot and shall certify the results thereof. No employer shall have standing as a party or to intervene in any representation proceeding under this section.