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 |
| --- | --- | --- | --- | --- | --- |
| Tennessee 1 | B. Carroll Reece | Republican | 1932.0 | Retired Republican hold | Dayton E. Phillips (R) Unopposed |
| Tennessee 3 | Estes Kefauver | Democratic | 1939.0 | Re-elected | Estes Kefauver (D) 90.8% George Bagwell (I) 9.2% |
| Tennessee 4 | Albert Gore, Sr. | Democratic | 1938.0 | Re-elected | Albert Gore, Sr. (D) 67.5% H. E. McLean (R) 32.5% |
| Tennessee 5 | Harold Earthman | Democratic | 1944.0 | Lost renomination Democratic hold | Joe L. Evins (D) Unopposed |
| Tennessee 6 | Percy Priest | Democratic | 1940.0 | Re-elected | Percy Priest (D) 77.1% Will T. Perry (R) 22.9% |
| Tennessee 7 | W. Wirt Courtney | Democratic | 1939.0 | Re-elected | W. Wirt Courtney (D) Unopposed |
| Tennessee 8 | Tom J. Murray | Democratic | 1942.0 | Re-elected | Tom J. Murray (D) Unopposed |
| Tennessee 9 | Jere Cooper | Democratic | 1928.0 | Re-elected | Jere Cooper (D) Unopposed |
Question:
When was the Tennessee 3 district incumbent first elected? 
Answer:
1939.0