Return DataSet from Npgsql with multiple result set as Tables

clsPSQLConnectionCreator dbHelper = new clsPSQLConnectionCreator();
        NpgsqlCommand sc = dbHelper.GetSqlQueryCommand("select * from systemtracker_dbo.pr_get_dataset('parameter1','parameter2','ref_cursor1','ref_cursor1','ref_cursor1','ref_cursor1','ref_cursor1','ref_cursor1','ref_cursor1','ref_cursor1');FETCH ALL IN t1; FETCH ALL IN t2;FETCH ALL IN t3;FETCH ALL IN t4;FETCH ALL IN t5;FETCH ALL IN t6;FETCH ALL IN t7;FETCH ALL IN t8;");

        DataSet ds = dbHelper.LoadDataSet(sc);
        return ds;

GetSqlQueryCommand function in helper class which consist connection as well 

    public NpgsqlCommand GetSqlQueryCommand(string query)
    {
        return PrepareCommand(CommandType.Text, query);
    }



 private NpgsqlCommand PrepareCommand(CommandType commandType, string commandText)
    {
        if (connection == null)
        {
            connection = new NpgsqlConnection(this.connectionString);
        }
        if (connection.State == ConnectionState.Closed || connection.State == ConnectionState.Broken)
        {
            connection.Open();
        }
        NpgsqlCommand command = new NpgsqlCommand(commandText, connection);
        command.CommandType = commandType;
        return command;
    }


public DataSet LoadDataSet(NpgsqlCommand command, string[] tableNames = null)
    {
        using (NpgsqlDataAdapter da = new NpgsqlDataAdapter(command))
        {
            using (DataSet ds = new DataSet())
            {
                da.Fill(ds);
                return ds;
            }
        }
    }