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:
| District | Incumbent | Party | First elected | Results |
| --- | --- | --- | --- | --- |
| Minnesota 1 | Gil Gutknecht | Republican | 1994.0 | Lost re-election Democratic gain |
| Minnesota 2 | John Kline | Republican | 2002.0 | Re-elected |
| Minnesota 3 | Jim Ramstad | Republican | 1990.0 | Re-elected |
| Minnesota 4 | Betty McCollum | Democratic | 2000.0 | Re-elected |
| Minnesota 5 | Martin Sabo | Democratic | 1978.0 | Retired Democratic hold |
| Minnesota 6 | Mark Kennedy | Republican | 2000.0 | Retired to run for U.S. Senate Republican hold |
| Minnesota 7 | Collin Peterson | Democratic | 1990.0 | Re-elected |
| Minnesota 8 | Jim Oberstar | Democratic | 1974.0 | Re-elected |
Question:
What is Incumbent, when Results is "Re-Elected", when Party is "Democratic", and when District is "Minnesota 7"?
Answer:
Collin Peterson