get data from Dataset

public DataSet GetPaymentMode(string CompanyId)
        {

            OleDbCommand cmdPermission = new OleDbCommand();
            if (Conn.State != ConnectionState.Open)
            {
                Conn.Open();
            }
            DataSet ds = new DataSet();
            cmdPermission.CommandText = "SELECT PaymentTerm from Company_Master where CompanyID=" + CompanyId + "";
            cmdPermission.CommandType = CommandType.Text;
            cmdPermission.Connection = Conn;
            cmdPermission.ExecuteNonQuery();
            OleDbDataAdapter adap = new OleDbDataAdapter(cmdPermission);
            if (Conn.State == ConnectionState.Open)
            {
                Conn.Close();
            }
            //adap.Fill(ds);
            return ds;
        }