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 | Result | Candidates |
| --- | --- | --- | --- | --- | --- |
| Louisiana 1 | F. Edward Hebert | Democratic | 1940.0 | Re-elected | F. Edward Hebert (D) Unopposed |
| Louisiana 2 | Hale Boggs | Democratic | 1946.0 | Re-elected | Hale Boggs (D) 67.2% David C. Treen (R) 32.8% |
| Louisiana 3 | Edwin E. Willis | Democratic | 1948.0 | Re-elected | Edwin E. Willis (D) Unopposed |
| Louisiana 4 | Joe Waggonner | Democratic | 1961.0 | Re-elected | Joe Waggonner (D) Unopposed |
| Louisiana 5 | Otto Passman | Democratic | 1946.0 | Re-elected | Otto Passman (D) Unopposed |
| Louisiana 6 | James H. Morrison | Democratic | 1942.0 | Re-elected | James H. Morrison (D) Unopposed |
Question:
Who were all the candidates when the first elected year was 1961?
Answer:
Joe Waggonner (D) Unopposed