Set the range of your retrieve to First And add a proper XPath constraint to filter the database on the right object.
By doing this, you will get the first item of the retrieved list.
//note//
The filter option Dinesh describes has in the end the same result. Big difference is that this will result in serverside filtering, while using a proper retrieve, the database will do the job. Which is in the end much better in performance
HI Cristian Olivares,
After the ‘Refacciones list’ Put an List Operation Activity and select Find/Find by Expression option nd select the list and attribute of the object you want to find.
Good Luck and Hope it helps!!