List Create node has elements, the code block is using a string. A string is not the same as an element, even though the element’s name is the same as the string.
What you want is the name of the element. Try the Element.Name node instead.
You are mixing up data types by trying to find out if the string “Branch_Rectangular Duct” exist in a list of elements. You can delete the list create node and feed the select elements into a string from object node and use a string.contains (note the string) instead of a list.contains, afterwards to get your list of elements use a FilterByBoolMask node.
Thank you! 