First check id tag on eng to see if eng a K181(8hp) or K241(10hp)the 110 tractor was made with both eng.
After eng disassembled,take block & crank to a local machine shop that does eng reboreing,have them check bore size of cyl to see if a std size piston will work or if a rebore needed & an os piston set installed,also have them measure crank rod journal to see if within spec's for a std size rod or if crank will need a grind/polish & an undersize rod installed or possibly a new crank needed.
After you find out if eng needs a rebore & possibly an undersize rod(shop will tell you os piston size set needed & also size of undersize rod if needed)you can lookup part#'s at link below,then order parts thru local mower shop,online kohler eng parts store,ebay or online dealers by doing a goggle search for kohler eng parts.You MUST have new piston/rod & take to shop along with block/crank if any machine work needed on eng so new parts can be test fit.
While you're sitting around goto www.kohlerengines.com & download/save & print service/repair manual for K series eng,look in section 1 of manual,it will give you bore size/crank journal size for your eng,write these numbers down & take them with you when you have bore/crank checked at shop.
Other possible options,check small engine warehouse online in repower section to see if a shortblock or other possible eng replacement avail.