CREATE TABLE table_name_37 (competing_entities VARCHAR(255), sport VARCHAR(255), age_groups VARCHAR(255), held_every VARCHAR(255))
what is the competing entities when the age group is 18 or younger, held every is one year and the sport is table tennis?
    
SQL: SELECT competing_entities FROM table_name_37 WHERE age_groups = "18 or younger" AND held_every = "one year" AND sport = "table tennis"