Reviewed by Judd Hollander The trick when presenting a biographical vehicle is to make sure the audience is able to relate to the subject in question. Especially if that subjects happen to be, in the words of director Robert O’Hara, “sexist, prejudiced, colorist, misogynist and elitist.” Fortunately, the Encores! production of the 1992 Broadway musical Jelly’s Last Jam, about the life of jazz pioneer Ferdinand Le Menthe “Jelly Roll” Morton (1891-1941), is able to do exactly that, and more.