CREATE TABLE table_203_3 (id DECIMAL, "province" TEXT, "capital" TEXT, "population" DECIMAL, "density" TEXT, "municipalities" TEXT, "legal districts" DECIMAL)

the population of cadiz is how much greater than jaen ?
SELECT (SELECT "population" FROM table_203_3 WHERE "province" = 'cadiz') - (SELECT "population" FROM table_203_3 WHERE "province" = 'jaen')
SELECT (SELECT "population" FROM "table_203_3" WHERE "province" = 'cadiz') - (SELECT "population" FROM "table_203_3" WHERE "province" = 'jaen')