CREATE TABLE table_24502 ("District" TEXT, "Vacator" TEXT, "Reason for change" TEXT, "Successor" TEXT, "Date successor seated" TEXT)

How many people vacated to successor Dave E. Satterfield, Jr. (d)?
SELECT COUNT("Vacator") FROM table_24502 WHERE "Successor" = 'Dave E. Satterfield, Jr. (D)'
SELECT COUNT("Vacator") FROM "table_24502" WHERE "Successor" = 'Dave E. Satterfield, Jr. (D)'