An organization of certificated employees which receives a majority of the valid votes cast in an election held in accordance with the rules of this part shall be recognized as representing the certificated employees of Community College District No. 20 pursuant to RCW 28.72.010 — 28.72.090. If more than one organization of certificated employees has participated in an election and a majority of the valid votes cast has not been either for representation by one of the organizations or for no representation, a run-off election shall be held. In such a run-off, only those two choices receiving the highest number of valid votes cast in the initial election shall appear on the ballot.