The Only thing you have to do is Change the query to:
"select top 1 id, col2, col3, col4, coln from Table_Test order by id desc"
By doing this, you will get only 1 row in the dataset. This row will be the last one present in your table.
In the query, 'id' is the Primary Key column and you have to write all column names from which you want data - In the above query, col2,col3,...coln are those columns.
Do this and you're done!