Give me a list of cities whose temperature in Mar is lower than that in Dec and which have never been host cities.
select t1.city from city as t1 join temperature as t2 on t1.city_id = t2.city_id where t2.mar < t2.dec except select t3.city from city as t3 join hosting_city as t4 on t3.city_id = t4.host_city