Well, if the one b. 1849 is with his parents Charles and Ann on the 1861 census, and the one b. 1853 is in the workhouse in 1861, then they must be different people - just like lizdb said.
But the only way to be sure (if you're sure that the one in the workhouse is "yours), is to buy his birth certificate. Are there any other Hewitts in the same workhouse who could be relatives?
STG