CREATE TABLE table_72359 ("District" TEXT, "Incumbent" TEXT, "Party" TEXT, "First elected" FLOAT, "Results" TEXT, "Candidates" TEXT)

What party does William J. Jefferson?
SELECT "Party" FROM table_72359 WHERE "Incumbent" = 'William J. Jefferson'
SELECT "Party" FROM "table_72359" WHERE "Incumbent" = 'William J. Jefferson'