user: Question: When 4 clubs are involved, what is the average number of fixtures?
Columns: ['Round', 'Date(s)', 'Clubs from the previous round', 'Clubs involved', 'Fixtures']
Types: ['text', 'text', 'text', 'real', 'real']
Sample row: ['First round', '3 September 2006', 'none', 127.0, 60.0]
SQL:

assistant: SELECT AVG("Fixtures") FROM "Table" WHERE "Clubs involved" = 4.0;