user: Question: Which the lowest Against has a Status of Tour Match, and a Venue of Ravenhill , Belfast?
Columns: ['Opposing Team', 'Against', 'Date', 'Venue', 'Status']
Types: ['text', 'real', 'text', 'text', 'text']
Sample row: ['Cambridge University', 12.0, '18 October 1978', 'Grange Road, Cambridge', 'Tour Match']
SQL:

assistant: SELECT MIN("Against") FROM "Table" WHERE "Status" = 'Tour Match' AND "Venue" = 'Ravenhill , Belfast';