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:
| Date | Opponent | City | Result | Score |
| --- | --- | --- | --- | --- |
| September 19 | Kansas | Lawrence | Win | 61-0 |
| September 26 | Northwestern | Evanston | Win | 20-12 |
| October 3 | Minnesota | Minneapolis | Win | 7-6 |
| October 10 | Michigan | Ann Arbor | Win | 26-14 |
| October 17 | Notre Dame | South Bend | Loss | 0-28 |
| October 31 | Indiana | Bloomington | Win | 26-6 |
| November 7 | Fort Knox | Louisville | Win | 13-7 |
| November 21 | Nebraska | Iowa City | Win | 46-0 |
| November 28 | Ohio State | Columbus | Loss | 12-41 |
| December 5 | Missouri | Kansas City | Loss | 0-7 |
Question:
Who was the opponent when the city was Louisville?
Answer:
Fort Knox