user: Question: Lowest against for Tour Match on 21 July 1990?
Columns: ['Opposing Team', 'Against', 'Date', 'Venue', 'Status']
Types: ['text', 'real', 'text', 'text', 'text']
Sample row: ['Banco Nación', 29.0, '14 July 1990', 'Buenos Aires', 'Tour Match']
SQL:

assistant: SELECT MIN("Against") FROM "Table" WHERE "Status" = 'Tour Match' AND "Date" = '21 July 1990';