CREATE TABLE table_204_799 (id DECIMAL, "name" TEXT, "built" TEXT, "listed" TEXT, "location" TEXT, "county" TEXT, "type" TEXT)

which of these bridges was the first one built ?
SELECT "name" FROM table_204_799 ORDER BY "built" LIMIT 1
SELECT "name" FROM "table_204_799" ORDER BY "built" NULLS FIRST LIMIT 1