CREATE TABLE farm_competition (Official_Name VARCHAR(255), City_ID VARCHAR(255), Host_city_ID VARCHAR(255)); CREATE TABLE city (Official_Name VARCHAR(255), City_ID VARCHAR(255), Host_city_ID VARCHAR(255))
List the official names of cities that have not held any competition.
    
SQL: SELECT Official_Name FROM city WHERE NOT City_ID IN (SELECT Host_city_ID FROM farm_competition)