CREATE TABLE table_48590 ("Date" TEXT, "Opponent" TEXT, "Score" TEXT, "Record" TEXT, "Streak" TEXT)

who is the opponent when the streak is won 9 on april 13, 1990?
SELECT "Opponent" FROM table_48590 WHERE "Streak" = 'won 9' AND "Date" = 'april 13, 1990'
SELECT "Opponent" FROM "table_48590" WHERE "Date" = 'april 13, 1990' AND "Streak" = 'won 9'