Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_18630 ( "District" text, "Incumbent" text, "Party" text, "First elected" real, "Result" text, "Candidates" text )

### Question ###
William Fadjo Cravens is the only candidate who was first elected in 1939.

### Accurate SQL ###

SELECT COUNT("First elected") FROM table_18630 WHERE "Incumbent" = 'William Fadjo Cravens'