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 |
| --- | --- | --- | --- | --- | --- |
| South Carolina 1 | L. Mendel Rivers | Democratic | 1940.0 | Re-elected | L. Mendel Rivers (D) Unopposed |
| South Carolina 2 | John J. Riley | Democratic | 1950.0 | Re-elected | John J. Riley (D) Unopposed |
| South Carolina 3 | William Jennings Bryan Dorn | Democratic | 1950.0 | Re-elected | William Jennings Bryan Dorn (D) Unopposed |
| South Carolina 4 | Robert T. Ashmore | Democratic | 1953.0 | Re-elected | Robert T. Ashmore (D) Unopposed |
| South Carolina 5 | Robert W. Hemphill | Democratic | 1956.0 | Re-elected | Robert W. Hemphill (D) Unopposed |
Question:
What is the earliest year that a candidate was first elected?
Answer:
1940.0