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_name_28 (first_elected VARCHAR, party VARCHAR, incumbent VARCHAR)

### Question ###
When was republican incumbent Joseph McKenna first elected?

### Accurate SQL ###

SELECT first_elected FROM table_name_28 WHERE party = "republican" AND incumbent = "joseph mckenna"