CREATE TABLE table_204_579 (id DECIMAL, "code" TEXT, "district" TEXT, "headquarters" TEXT, "population  ( as of 2011 ) " DECIMAL, "area  ( km2 ) " DECIMAL, "density  ( /km2 ) " DECIMAL)

what is the last code listed ?
SELECT "code" FROM table_204_579 ORDER BY id DESC LIMIT 1
SELECT "code" FROM "table_204_579" ORDER BY "id" DESC NULLS LAST LIMIT 1