Issue with ON DUPLICATE KEY UPDATE in mvc

I have following query written in my c# class.

string query = @"INSERT INTO UserPersonalInfo(col1,col2,col3)
                VALUES (@c1,@c2,@c3) ON DUPLICATE KEY UPDATE col2 = @c2, col3= @c3";
query += " SELECT SCOPE_IDENTITY()";

But I am getting following error while running above query,

Incorrect syntax near the keyword 'ON'.