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 | Opponent | Result | Attendance |
| --- | --- | --- | --- | --- |
| 1 | September 26, 1959 | at Los Angeles Rams | W 23–21 | 71,297 |
| 2 | October 4, 1959 | at Philadelphia Eagles | L 49–21 | 27,023 |
| 3 | October 11, 1959 | at Cleveland Browns | W 10–6 | 65,534 |
| 4 | October 18, 1959 | Philadelphia Eagles | W 24–7 | 68,783 |
| 5 | October 25, 1959 | at Pittsburgh Steelers | W 21–16 | 33,596 |
| 6 | November 1, 1959 | Green Bay Packers | W 20–3 | 68,837 |
| 7 | November 8, 1959 | Chicago Cardinals | W 9–3 | 56,779 |
| 8 | November 15, 1959 | Pittsburgh Steelers | L 14–9 | 66,786 |
| 9 | November 22, 1959 | at Chicago Cardinals (Bloomington, MN) | W 30–20 | 26,625 |
| 10 | November 29, 1959 | Washington Redskins | W 45–14 | 60,982 |
| 11 | December 6, 1959 | Cleveland Browns | W 48–7 | 68,436 |
| 12 | December 13, 1959 | at Washington Redskins | W 24–10 | 26,198 |
Question:
when was their last loss?
Answer:
November 15, 1959