CREATE TABLE table_204_522 (id DECIMAL, "boat #" TEXT, "name" TEXT, "builder" TEXT, "laid down" TEXT, "launched" TEXT, "completed" TEXT, "fate" TEXT)

when was a boat launched immediately before ha-206 ?
SELECT "name" FROM table_204_522 WHERE "launched" < (SELECT "launched" FROM table_204_522 WHERE "name" = 'ha-206') ORDER BY "launched" DESC LIMIT 1
SELECT "name" FROM "table_204_522" WHERE "launched" < (SELECT "launched" FROM "table_204_522" WHERE "name" = 'ha-206') ORDER BY "launched" DESC NULLS LAST LIMIT 1