Dataset- Filter Row Through DefaultView

SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["SchoolsConnectionString"].ConnectionString);
DataSet ds = new DataSet();
SqlDataAdapter adp = new SqlDataAdapter("select * from students", con);
Dataset ds = new DataSet();
adp.Fill(ds);
string message;
ds.Tables[0].DefaultView.RowFilter = "Name='Subhash'";
if (ds.Tables[0].DefaultView.Count != 0)
{
message = ds.Tables[0].DefaultView[0].Row["LastName"].ToString();
}
else
{
message = "";
}