<table id="tb">
            <tr>
                <td>0</td>
                <td>1</td>
                <td>2</td>
            </tr>
            <tr>
                <td>3</td>
                <td>4</td>
                <td>5</td>
            </tr>
 </table>

$("#tb>tbody").children("tr:eq(1) td:eq(1)").html()

$("#tb>tbody").find("tr:eq(1) td:eq(1)").html()

$("#tb>tbody").children("tr:last").children("td:eq(1)").html()