Name the district for  rep. warren r. davis died during previous congress
CREATE TABLE "table1_225200_4" (
  "district" text,
  "vacator" text,
  "reason_for_change" text,
  "successor" text,
  "date_successor_seated" text
);
SELECT "district" FROM "table1_225200_4" WHERE "reason_for_change"='Rep. Warren R. Davis died during previous congress';