#Short Answer
Instead of LEFT() use RIGHT().

#Explanation

The LEFT() function returns the leftmost characters, but the OP want to get the rightmost characters. 

The following is a simplified version of the final formula, for explanatory purposes:

    =RIGHT("Sector: Industrial Goods",16)

The following is the final formula; in order to improve readability, each parameter is inserted in a new line:

     =RIGHT(
       iferror(
         INDEX(
           IMPORTHTML(
             "http://www.thestreet.com/quote/GE/details/company-profile.html",
              "table",
              3
            ),
            8,
            1
         )
       ),
       16
     )