using System;

using System.Linq;

using System.Xml.Linq;

​

public class Program

{

    public static void Main()

    {

        const string xml = @"<param name=""C01""> <comm>30313</comm> <command>INA</command> <factor>5</factor> <index>2</index> <meter>0</meter> <player>1023</player> <meterstring>ml_BET</meterstring> </param>";

        var doc = XDocument.Parse(xml);

        var comm = doc.Descendants("param")

            .Where(x => (string)x.Attribute("name") == "C01")

            .Elements("comm")

            .Single();

        Console.WriteLine(comm.Value);

    }

}