user: Question: what is the sport when the age group is 21 or younger and the competition name is World Youth Netball Championships?
Columns: ['Sport', 'Competition name', 'Competing entities', 'Age groups', 'Held every']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Aquatics', 'FINA World Junior Swimming Championships', 'Individuals [R ]', '17 or younger', 'Two years']
SQL:

assistant: SELECT "Sport" FROM "Table" WHERE "Age groups" = '21 or younger' AND "Competition name" = 'World Youth Netball Championships';