user: Question: Who was the opponent before week 6 at Cleveland Municipal Stadium?
Columns: ['Week', 'Date', 'Opponent', 'Result', 'Game site', 'Record', 'Attendance']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'real']
Sample row: [1.0, 'September 8, 1985', 'Green Bay Packers', 'W 26–20', 'Sullivan Stadium', '1–0', 49488.0]
SQL:

assistant: SELECT "Opponent" FROM "Table" WHERE "Week" < 6.0 AND "Game site" = 'Cleveland Municipal Stadium';