(a) The question of whether the Board will assert jurisdiction over a labor dispute which is the subject of a proceeding in an agency or court of a State or territory is initiated by the filing of a petition with the Board. This petition may be filed only if:

(1) A proceeding is currently pending before such agency or court;

(2) The petitioner is the agency or court itself; and

(3) The relevant facts are undisputed or the agency or court has already made the relevant factual findings.

(b) The petition must be in writing and signed. It is filed with the Executive Secretary of the Board in Washington, DC. No particular form is required, but the petition must be properly captioned and must contain the allegations required by section 102.99 of the Board's Rules and Regulations. None of the information sought may relate to the merits of the dispute. The petition may be withdrawn at any time before the Board issues its advisory opinion determining whether it would or would not assert jurisdiction on the basis of the facts before it.