CREATE TABLE table_204_231 (id DECIMAL, "rank" DECIMAL, "nation" TEXT, "gold" DECIMAL, "silver" DECIMAL, "bronze" DECIMAL, "total" DECIMAL)

the difference between the number of medals of italy and the number of medals of poland
SELECT (SELECT "total" FROM table_204_231 WHERE "nation" = 'italy') - (SELECT "total" FROM table_204_231 WHERE "nation" = 'poland')
SELECT (SELECT "total" FROM "table_204_231" WHERE "nation" = 'italy') - (SELECT "total" FROM "table_204_231" WHERE "nation" = 'poland')