You can do it like below one
use style propery of both control
<table width="100%">
<tr>
<td>
<asp:Panel id="pnl1" runat="server" style="top:0'"></asp:Panel>
<asp:Label ID="lbl1" runat="server" Text="test" style="bottom:0px"></asp:Label>
</td>
</tr>
</table>