What am I missing with this query?

This code works:

$querystate = "select download_playlist.id, download_playlist.contestant_id, download_playlist.playlist_name, registration.id, registration.first_name, registration.last_name, registration.song_title from download_playlist, registration where
                              download_playlist.contestant_id = registration.id order by registration.song_title";

But when I try to retrieve the download_playlist.id value using:

echo $row['download_playlist.id'], I get nothing.

If I put, echo $row['id'], I'll get the id from the registration table, but I need to get the id from the download_playlist table. How?