What is the code of the area with the largest Asian population?
the code of the area refers to area_code; area with the largest Asian population refers to MAX(asian_population);
SELECT T1.zip_code FROM area_code AS T1 INNER JOIN zip_data AS T2 ON T1.zip_code = T2.zip_code GROUP BY T2.asian_population ORDER BY T2.asian_population DESC LIMIT 1