How many people vacated to successor Dave E. Satterfield, Jr. (d)?
CREATE TABLE "table1_2159547_3" (
  "district" text,
  "vacator" text,
  "reason_for_change" text,
  "successor" text,
  "date_successor_seated" text
);
SELECT COUNT("vacator") FROM "table1_2159547_3" WHERE "successor"='Dave E. Satterfield, Jr. (D)';