You can filter out the first row based on its style, color property then match for 1st and 3rd column by using the xpath position function. The corresponding XPath expression would be:
//table[@id='GridView1']/tbody/tr[contains(@style,'color:#333333')]/td[position()=1 or position()=3]
With the following test input, you can test it here.
<table id="GridView1">
<tbody>
<tr style="color:White"><td>header1</td><td>header2</td><td>header3</td><td>header4</td></tr>
<tr style="color:#333333"><td>data1</td><td>data2</td><td>data3</td><td>data4</td></tr>
<tr style="color:#333333"><td>data12</td><td>data22</td><td>data32</td><td>data42</td></tr>
<tr style="color:#333333"><td>data13</td><td>data23</td><td>data33</td><td>data43</td></tr>
<tr style="color:#333333"><td>data14</td><td>data24</td><td>data34</td><td>data44</td></tr>
<tr style="color:#333333"><td>data15</td><td>data25</td><td>data35</td><td>data45</td></tr>
<tr style="color:#333333"><td>data16</td><td>data26</td><td>data36</td><td>data46</td></tr>
<tr style="color:#333333"><td>data17</td><td>data27</td><td>data37</td><td>data47</td></tr>
<tr style="color:#333333"><td>data18</td><td>data28</td><td>data38</td><td>data48</td></tr>
<tr style="color:#333333"><td>data19</td><td>data29</td><td>data39</td><td>data49</td></tr>
</tbody>
</table>
The output should be according to the imgae below, only cells starting with data1
and data3
should match as those are the ones from column 1 and 3.

findElement
relative to a webelement to get the values. Still did not understand what issue you have :( – Dakshinamurthy Karra Sep 25 '18 at 11:47