When was the incumbent first elected in the district where the result was a democratic-republican gain? 
CREATE TABLE table_2668401_17 (first_elected VARCHAR, result VARCHAR)
SELECT first_elected FROM table_2668401_17 WHERE result = "Democratic-Republican gain"
<s>[INST] Write mssql query to answer the following question given the database schema. Schema: 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?  [/INST] SELECT first_elected FROM table_2668401_17 WHERE result = "Democratic-Republican gain" </s>