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:
List of Chief Ministers of Delhi
Table title:
List of Chief Ministers of Delhi
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=1 > No </th><th colspan=1 rowspan=1 > Name (constituency) </th><th colspan=1 rowspan=1 > Portrait </th><th colspan=1 rowspan=1 > Term (tenure length) </th><th colspan=2 rowspan=1 > Party </th><th colspan=1 rowspan=1 > Tenure </th><th colspan=1 rowspan=1 > Assembly (Election) </th></tr>
<tr> <td colspan=1 rowspan=1 > 1 </td><td colspan=1 rowspan=1 > Chaudhary Brahm Prakash (Nangloi) </td><td colspan=1 rowspan=1 > - </td><td colspan=1 rowspan=1 > 17 March 1952 – 12 February 1955 (2 years, 332 days) </td><td colspan=1 rowspan=2 > Indian National Congress </td><td colspan=1 rowspan=2 >  </td><td colspan=1 rowspan=1 > 1062 days </td><td colspan=1 rowspan=2 > Interim Assembly (1952–56) (1952 election) </td></tr>
<tr> <td colspan=1 rowspan=1 > 2 </td><td colspan=1 rowspan=1 > Gurmukh Nihal Singh (Darya Ganj) </td><td colspan=1 rowspan=1 > – </td><td colspan=1 rowspan=1 > 12 February 1955 – 1 November 1956 (1 year, 263 days) </td><td colspan=1 rowspan=1 > 628 days </td></tr>
<tr> <th colspan=8 rowspan=1 > Office abolished, 1956–93 </th></tr>
<tr> <td colspan=1 rowspan=1 > 3 </td><td colspan=1 rowspan=1 > Madan Lal Khurana (Moti Nagar) </td><td colspan=1 rowspan=1 > - </td><td colspan=1 rowspan=1 > 2 December 1993 – 26 February 1996 (2 years, 86 days) </td><td colspan=1 rowspan=3 > Bharatiya Janata Party </td><td colspan=1 rowspan=3 >  </td><td colspan=1 rowspan=1 > 816 days </td><td colspan=1 rowspan=3 > First Assembly (1993–98) (1993 election) </td></tr>
<tr> <td colspan=1 rowspan=1 > 4 </td><td colspan=1 rowspan=1 > Sahib Singh Verma (Shalimar Bagh) </td><td colspan=1 rowspan=1 > - </td><td colspan=1 rowspan=1 > 26 February 1996 – 12 October 1998 (2 years, 228 days) </td><td colspan=1 rowspan=1 > 959 days </td></tr>
<tr> <td colspan=1 rowspan=1 > 5 </td><td colspan=1 rowspan=1 > Sushma Swaraj </td><td colspan=1 rowspan=1 > - </td><td colspan=1 rowspan=1 > 12 October 1998 – 3 December 1998 (52 days) </td><td colspan=1 rowspan=1 > 52 days </td></tr>
<tr> <td colspan=1 rowspan=3 > 6 </td><td class="highlighted"  colspan=1 rowspan=3 > Sheila Dikshit (New Delhi) </td><td colspan=1 rowspan=3 > - </td><td class="highlighted"  colspan=1 rowspan=1 > 3 December 1998 – 1 December 2003 (4 years, 363 days) </td><td colspan=1 rowspan=3 > Indian National Congress </td><td colspan=1 rowspan=3 >  </td><td colspan=1 rowspan=3 > 5504 days </td><td colspan=1 rowspan=1 > Second Assembly (1998–2003) (1998 election) </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > 1 December 2003 – 29 October 2008 (4 years, 333 days) </td><td colspan=1 rowspan=1 > Third Assembly (2003-08) (2003 election) </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > 29 October 2008 – 28 December 2013 (5 years, 60 days) </td><td colspan=1 rowspan=1 > Fourth Assembly (2008–13) (2008 election) </td></tr>
<tr> <td colspan=1 rowspan=1 > 7 </td><td colspan=1 rowspan=1 > Arvind Kejriwal (New Delhi) </td><td colspan=1 rowspan=1 > - </td><td colspan=1 rowspan=1 > 28 December 2013 – 14 February 2014 (48 days) </td><td colspan=1 rowspan=1 > Aam Aadmi Party </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > 48 days </td><td colspan=1 rowspan=2 > Fifth Assembly (2013-15) (2013 election) </td></tr>
<tr> <td colspan=1 rowspan=1 > – </td><td colspan=1 rowspan=1 > President's rule </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > 14 February 2014 – 14 February 2015 (1 year, 0 days) </td><td colspan=1 rowspan=1 > N/A </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > 365 days </td></tr>
<tr> <td colspan=1 rowspan=1 > (7) </td><td colspan=1 rowspan=1 > Arvind Kejriwal (New Delhi) </td><td colspan=1 rowspan=1 > - </td><td colspan=1 rowspan=1 > 14 February 2015 – present (4 years, 75 days) </td><td colspan=1 rowspan=1 > Aam Aadmi Party </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > 1536 days (1584 days) </td><td colspan=1 rowspan=1 > Sixth Assembly (2015–20) (2015 election) </td></tr>
</table>
Question:
Who was the longest serving Chief Minister of Delhi, and what years did he serve?
Answer:
Sheila Dikshit was the longest serving Chief Minister of Delhi from 1998 to 2013.