Which model saves the most gasoline? That is to say, have the maximum miles per gallon.
SELECT T1.Model FROM CAR_NAMES AS T1 JOIN CARS_DATA AS T2 ON T1.MakeId  =  T2.Id ORDER BY T2.mpg DESC LIMIT 1;
SELECT T1.Model FROM CAR_NAMES AS T1 JOIN CARS_DATA AS T2 ON T1.MakeId  =  T2.Id ORDER BY T2.mpg DESC LIMIT 1;
[{'Model': 'citroen'}]