Why is SqlDataReader returning data in different order in Web API

I am converting an old application to Web API and noticed a strange behaviour. I'm executing a simple select statement to fetch records.

select top 10 
      name, weight, id 
from 
     tblA TA 
inner join 
     tblB TB on TA.id = TB.id 
where 
     id = @id 
ORDER BY 
     weight desc 

Unlike a similar question asked on SO, I am using ORDER BY clause in my query and this is working absolutely fine in old application. The data type for column weight is int.

My C# code in the application is:

            List<People> people = new List<People>();    

            SqlCommand cmd = new SqlCommand();
            cmd.Connection = _conn;
            cmd.CommandType = System.Data.CommandType.Text;
            cmd.CommandText = strSQLText;

            // add parameters
            cmd.Parameters.AddWithValue("@id", ID);

            SqlDataReader sdrPerson;
            sdrPerson= cmd.ExecuteReader();

            using (sdrPerson)
            {
                while (sdrPerson.Read())
                {
                    Person _person = new Person();
                    _person.name = sdrPerson["name"].ToString().Trim();
                    _person.id = Convert.ToInt32(sdrPerson["id"].ToString().Trim());

                    //add person to people list                       
                    people.Add(_person);
                }
            }

The issue: Query is doing order by but the SqlDataReader reads in different order. The query returns 10 rows and out of them one has weight value of 5 and others have value of 7. When ordered DESC, the top 9 rows just come randomly while the last one is always at the bottom or the output. And strangely it only happens if I order DESC and works fine with ASC. Query runs all good in sql server management studio.

The code is absolutely simple and I expected it to work right away. Why is this happening? Is there an issue with Web API or am I doing something wrong here? Or if the more than 1 row have same value for the order by column, does SqlDataReader do random ordering? I've never come across this before.

Sample output:

<people>
<person>
    <id>1234</id>
    <name>Mike</name>
</person>
<person>
    <id>4545</id>
    <name>Sally</name>
</person>
<person>
    <id>576565</id>
    <name>Ben</name>
</person>
<person>
    <id>66107</id>
    <name>Spyro</name>
</person>
<person>
    <id>54879</id>
    <name>Pat</name>
</person>
<person>
    <id>54876</id>
    <name>Kate</name>
</person>
<person>
    <id>40584</id>
    <name>Larry</name>
</person>
<person>
    <id>35742</id>
    <name>John</name>
</person>
<person>
    <id>26432</id>
    <name>George</name>
</person>