CREATE TABLE table_61231 ("Ship" CLOB, "Hull Number" CLOB, "Laid down" CLOB, "Launched" CLOB, "Commissioned" CLOB)

What is Launched, when Laid Down is '31 October 1981'?
SELECT "Launched" FROM table_61231 WHERE "Laid down" = '31 october 1981'
SELECT "Launched" FROM "table_61231" WHERE "Laid down" = '31 october 1981'