CREATE TABLE table_731 ("District" TEXT, "Incumbent" TEXT, "Party" TEXT, "First elected" FLOAT, "Result" TEXT, "Candidates" TEXT)

What's the district that Otto Passman is the incumbent of?
SELECT "District" FROM table_731 WHERE "Incumbent" = 'Otto Passman'
SELECT "District" FROM "table_731" WHERE "Incumbent" = 'Otto Passman'