DadaCompanion.com has published a useful list of exhibitions.

"The following [list] is offered not as a complete list of exhibitions by Marcel Duchamp, but as a comprehensive selection intended to give a survey of his activities and the way his work came to be known. Invaluable sources for a complete listing are the publications by Francis M. Naumann and Hector Obalk and Timothy Shipe for Arturo Schwarz."

source http://www.dada-companion.com/duchamp/exhibitions.php