CREATE TABLE table_24497 ("District" TEXT, "Vacator" TEXT, "Reason for change" TEXT, "Successor" TEXT, "Date successor seated" TEXT)

Who is every vacator with reason for change as resigned December 31, 1959?
SELECT "Vacator" FROM table_24497 WHERE "Reason for change" = 'Resigned December 31, 1959'
SELECT "Vacator" FROM "table_24497" WHERE "Reason for change" = 'Resigned December 31, 1959'