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_2668401_17 ( first_elected VARCHAR, result VARCHAR )

### Question ###
When was the incumbent first elected in the district where the result was a democratic-republican gain?

### Accurate SQL ###

SELECT first_elected FROM table_2668401_17 WHERE result = "Democratic-Republican gain"