Give me a list of cities whose temperature in Mar is lower than that in July and which have also served as host cities?
select t1.city from city as t1 join temperature as t2 on t1.city_id = t2.city_id where t2.mar < t2.jul intersect select t3.city from city as t3 join hosting_city as t4 on t3.city_id = t4.host_city