CREATE TABLE table_204_489 (id DECIMAL, "rank" DECIMAL, "name" TEXT, "height" TEXT, "floors" DECIMAL, "year" DECIMAL, "notes" TEXT)

what is the number of floors of the oldest building ?
SELECT "floors" FROM table_204_489 ORDER BY "year" LIMIT 1
SELECT "floors" FROM "table_204_489" ORDER BY "year" NULLS FIRST LIMIT 1