This April 4, 2013 photo released by NBC shows Jimmy Fallon, host of "Late Night with Jimmy Fallon," in New York. The role of female talk-show hosts in late-night TV network history, all 50-plus years of it, can be summed up in two words: Joan Rivers. It takes just another two _ Arsenio Hall _ to do the same for minorities. There's no indication that's going to change in the latest round of musical chairs involving "Tonight" and "Late Night."