Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Week | Date | Kickoff ( ET ) | Opponent | Result | Record | Game Site |
| --- | --- | --- | --- | --- | --- | --- |
| 1.0 | Mon. Sep. 3 | 9:00pm | at New England Patriots | W 16–13 OT | 1–0 | Schaefer Stadium |
| 2.0 | Sun. Sep. 9 | 1:00pm | Houston Oilers | W 38–7 | 2–0 | Three Rivers Stadium |
| 3.0 | Sun. Sep. 16 | 4:00pm | at St. Louis Cardinals | W 24–21 | 3–0 | Busch Memorial Stadium |
| 4.0 | Sun. Sep. 23 | 1:00pm | Baltimore Colts | W 17–13 | 4–0 | Three Rivers Stadium |
| 5.0 | Sun. Sep. 30 | 1:00pm | at Philadelphia Eagles | L 17–14 | 4–1 | Veterans Stadium |
| 6.0 | Sun. Oct. 7 | 4:00pm | at Cleveland Browns | W 51–35 | 5–1 | Cleveland Municipal Stadium |
| 7.0 | Sun. Oct. 14 | 1:00pm | at Cincinnati Bengals | L 34–10 | 5–2 | Riverfront Stadium |
| 8.0 | Mon. Oct. 22 | 9:00pm | Denver Broncos | W 42–7 | 6–2 | Three Rivers Stadium |
| 9.0 | Sun. Oct. 28 | 1:00pm | Dallas Cowboys | W 14–3 | 7–2 | Three Rivers Stadium |
| 10.0 | Sun. Nov. 4 | 1:00pm | Washington Redskins | W 38–7 | 8–2 | Three Rivers Stadium |
| 11.0 | Sun. Nov. 11 | 1:00pm | at Kansas City Chiefs | W 30–3 | 9–2 | Arrowhead Stadium |
| 12.0 | Sun. Nov. 18 | 4:00pm | at San Diego Chargers | L 35–7 | 9–3 | San Diego Stadium |
| 13.0 | Sun. Nov. 25 | 1:00pm | Cleveland Browns | W 33–30 OT | 10–3 | Three Rivers Stadium |
| 14.0 | Sun. Dec. 2 | 1:00pm | Cincinnati Bengals | W 37–17 | 11–3 | Three Rivers Stadium |
| 15.0 | Mon. Dec. 10 | 9:00pm | at Houston Oilers | L 20–17 | 11–4 | Astrodome |
| 16.0 | Sun. Dec. 16 | 1:00pm | Buffalo Bills | W 28–0 | 12–4 | Three Rivers Stadium |
Question:
Who was the opponent at the Steelers game that had a result of l 20–17?
Answer:
at Houston Oilers