CREATE TABLE table_204_649 (id DECIMAL, "rank" DECIMAL, "name" TEXT, "image" DECIMAL, "height\ ft  ( m ) " TEXT, "floors" DECIMAL, "year" DECIMAL, "notes" TEXT)

which building is the tallest ?
SELECT "name" FROM table_204_649 ORDER BY "height\nft (m)" DESC LIMIT 1
SELECT "name" FROM "table_204_649" ORDER BY "height\nft (m)" DESC NULLS LAST LIMIT 1