Name the district for reason for change being died july 4, 1939
CREATE TABLE "table1_2160008_4" (
  "district" text,
  "vacator" text,
  "reason_for_change" text,
  "successor" text,
  "date_successor_seated" text
);
SELECT "district" FROM "table1_2160008_4" WHERE "reason_for_change"='Died July 4, 1939';