Table schema:
CREATE TABLE table_name_15 (facility_id INTEGER, city_of_license VARCHAR, erp___power_w VARCHAR)

Question: Which Facility ID has a City of license of springfield, ma, and a ERP / Power W smaller than 230?
SQL: SELECT MAX(facility_id) FROM table_name_15 WHERE city_of_license = "springfield, ma" AND erp___power_w < 230