Top 20 resolved dates which take most time to resolve

i am working on SQL report builder and i have two tables as "incident created date" and "resolved date".

in resolved date table total time taken to resolve the incident.

i have to find top 20 incidents which took highest resolution time.

created date                              resolved date                 ID

20001125 10:25:03                  20001125 12:50:25       SP000546

20001125 10:30:11                  20001125 11:44:54       SP123655

20001125 11:25:32                  20001125 16:24:47       SP456982

20001125 14:11:11                  20001125 17:54:57       SP235568

table formart is like this

kindly any one help me what type of querry i used to figured out this.

Thanks in advance

Regards

M Ahsan