CREATE TABLE table_203_400 (id DECIMAL, "district" TEXT, "vacator" TEXT, "reason for change" TEXT, "successor" TEXT, "date successor\ seated" TEXT)

who was catherine s. long 's previous representative ?
SELECT "vacator" FROM table_203_400 WHERE "successor" = 'catherine s. long'
SELECT "vacator" FROM "table_203_400" WHERE "successor" = 'catherine s. long'