CREATE TABLE table_59833 ("Date" TEXT, "Round" TEXT, "Opponent" TEXT, "Venue" TEXT, "Result" TEXT, "Attendance" FLOAT)

What is the round for the opponent CSKA Sofia in Venue A?
SELECT "Round" FROM table_59833 WHERE "Opponent" = 'cska sofia' AND "Venue" = 'a'
SELECT "Round" FROM "table_59833" WHERE "Opponent" = 'cska sofia' AND "Venue" = 'a'