using System;

using System.Collections.Generic;

using System.Linq;

​

public class Program

{

    public static void Main(string[] args)

    {

        var items = new[]

        {

            new[] {"0", "John"},

                new[] {"1", "Mike"},

                new[] {"2", "John"},

                new[] {"3", "Tim"},

        };

        var distinct = items.Distinct(new SecondIndexComparer()).ToList();

        foreach (var item in distinct)

        {

            Console.WriteLine("{0} {1}", item[0], item[1]);

        }

    }

    private class SecondIndexComparer : IEqualityComparer<string[]>

    {

        public bool Equals(string[] x, string[] y)

        {

            return x[1] == y[1];

        }

        public int GetHashCode(string[] obj)

        {

            return obj[1].GetHashCode();

        }

    }

}