Please read the following table in HTML format from a webpage and then answer the question in detail according to the table. Each table cell is defined by a <td> and a </td> tag. Each table row starts with a <tr> and ends with a </tr> tag. 'rowspan=m' and 'colspan=n' represents a cell spaning over 'm' rows and 'n' columns.

Webpage title:
1920 Rhondda West by-election
Table title:

Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=2 rowspan=1 > Party </th><th colspan=1 rowspan=1 > Candidate </th><th colspan=1 rowspan=1 > Votes </th><th colspan=1 rowspan=1 > % </th><th colspan=1 rowspan=1 > ± </th></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td class="highlighted"  colspan=1 rowspan=1 > Labour </td><td class="highlighted"  colspan=1 rowspan=1 > William John </td><td class="highlighted"  colspan=1 rowspan=1 > 14,035 </td><td colspan=1 rowspan=1 > 58.5 </td><td colspan=1 rowspan=1 > N/A </td></tr>
<tr> <td colspan=1 rowspan=1 > C </td><td colspan=1 rowspan=1 > Unionist </td><td class="highlighted"  colspan=1 rowspan=1 > Gwilym Rowlands </td><td class="highlighted"  colspan=1 rowspan=1 > 9,959 </td><td colspan=1 rowspan=1 > 41.5 </td><td colspan=1 rowspan=1 > N/A </td></tr>
<tr> <th colspan=3 rowspan=1 > Majority </th><td class="highlighted"  colspan=1 rowspan=1 > 4,076 </td><td colspan=1 rowspan=1 > 17.0 </td><td colspan=1 rowspan=1 > N/A </td></tr>
<tr> <th colspan=3 rowspan=1 > Turnout </th><td colspan=1 rowspan=1 > 23,949 </td><td colspan=1 rowspan=1 > 70.2 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=2 rowspan=1 > Labour hold </td><th colspan=1 rowspan=1 > Swing </th><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=6 rowspan=1 > C indicates candidate endorsed by the coalition government. </td></tr>
</table>
Question:
Who won the 1920 Rhondda West by-election  for which party, and by how many votes over which candidate?
Answer:
The 1920 Rhondda West by-election result was a victory for the Labour candidate, William John, who won with a majority of 4,076 votes over Gwilym Rowlands.