[jQuery] Beginners problem with selectors

Hi, sorry if I am posting in the wrong group?

I am having a simple nested table, looks like this

<table id=mytable>
<tbody>
<tr>
<td>test</td>
<td><table><tr><td>New test</td></tr></table></td>
</tr>
</tbody>
</table>

So my problem is that I cant get the last TR within the first table?

var Obj = $("table#list tbody>tr:last");

Of course it looks at the last <tr> in the table, but how should I
manage to get the last TR in the first table?

Best regards, Joakim