CREATE TABLE table_204_882 (id NUMBER, "number" NUMBER, "builder" CLOB, "entered service" CLOB, "withdrawn" CLOB, "notes" CLOB)

which numbers were not withdrawn from service in 1957 ?
SELECT "number" FROM table_204_882 WHERE "withdrawn" <> 1957
SELECT "number" FROM "table_204_882" WHERE "withdrawn" <> 1957