List the name and city of starting stations which has an above-average duration trips.
starting stations refers to start_station_name; above average duration trips = DIVIDE(SUM(duration), COUNT(main_trip.id))<duration;
SELECT DISTINCT T1.start_station_name, T2.city FROM trip AS T1 INNER JOIN station AS T2 ON T2.name = T1.start_station_name WHERE T1.duration > ( SELECT AVG(T1.duration) FROM trip AS T1 LEFT JOIN station AS T2 ON T2.name = T1.start_station_name )