What district is Samuel A. Bridges ( D ) assigned to as a successor?
CREATE TABLE "table1_228439_4" (
  "district" text,
  "vacator" text,
  "reason_for_change" text,
  "successor" text,
  "date_successor_seated" text
);
SELECT "district" FROM "table1_228439_4" WHERE "successor"='Samuel A. Bridges ( D )';