If a landlord brings an action for possession under ORS 90.403 and the person in possession contends that the tenant has not vacated the premises, the burden of proof is on the defendant as to that issue. [1983 c.303 §3; 1993 c.369 §34; 2003 c.378 §21; 2005 c.22 §81; 2005 c.391 §30]