CREATE TABLE table_204_431 (id DECIMAL, "yacht" TEXT, "nation" TEXT, "owner" TEXT, "skipper" TEXT, "launch year" DECIMAL)

which yacht launched first : cougar ii or aurora ?
SELECT "yacht" FROM table_204_431 WHERE "yacht" IN ('cougar ii', 'aurora') ORDER BY "launch year" LIMIT 1
SELECT "yacht" FROM "table_204_431" WHERE "yacht" IN ('cougar ii', 'aurora') ORDER BY "launch year" NULLS FIRST LIMIT 1