user: Question: WhAt is the round for the opponent CSKA SofiA in Venue A?
Columns: ['Date', 'Round', 'Opponent', 'Venue', 'Result', 'Attendance']
Types: ['text', 'text', 'text', 'text', 'text', 'real']
Sample row: ['16 September 1970', 'R1', 'Aris Salonika', 'A', '1-1', 50000.0]
SQL:

assistant: SELECT "Round" FROM "Table" WHERE "Opponent" = 'CSKA Sofia' AND "Venue" = 'A';