2017 ORS 105.015¹
Answer

The defendant shall not be allowed to give in evidence any estate, license or right of possession in the property in the defendant or another, unless the same is pleaded in the answer. If pleaded, the nature and duration of the estate, license or right of possession shall be set forth with the certainty and particularity required in a complaint. If the defendant does not defend for the whole of the property, the defendant shall specify for what particular part the defendant does defend.

Chapter 105

Atty. Gen. Opinions

Private process server in a forcible entry and detainer ac­tion, (1975) Vol 37, p 869

1 Legislative Counsel Committee, CHAPTER 105—Property Rights, https://­www.­oregonlegislature.­gov/­bills_laws/­ors/­ors105.­html (2017) (last ac­cessed Mar. 30, 2018).
 
2 Legislative Counsel Committee, Annotations to the Oregon Revised Stat­utes, Cumulative Supplement - 2017, Chapter 105, https://­www.­oregonlegislature.­gov/­bills_laws/­ors/­ano105.­html (2017) (last ac­cessed Mar. 30, 2018).
 
3 OregonLaws.org assembles these lists by analyzing references between Sections. Each listed item refers back to the current Section in its own text. The result reveals relationships in the code that may not have otherwise been apparent.