CREATE TABLE table_203_515 (id DECIMAL, "rank" DECIMAL, "city" TEXT, "passengers" DECIMAL, "ranking" DECIMAL, "airline" TEXT)

how many more passengers flew to los angeles than to saskatoon from manzanillo airport in 2013 ?
SELECT (SELECT "passengers" FROM table_203_515 WHERE "city" = 'los angeles') - (SELECT "passengers" FROM table_203_515 WHERE "city" = 'saskatoon')
SELECT (SELECT "passengers" FROM "table_203_515" WHERE "city" = 'los angeles') - (SELECT "passengers" FROM "table_203_515" WHERE "city" = 'saskatoon')