You could create a rule such as
If [Valid Last Week]=1 then null
elseif [Valid This Week]=1 then 1
and then place this on the Filter shelf so only the the values of 1 are retained in the data.
What's the need for the underlying data rather than just creating a report/view in Tableau that shows the values meeting the condition? I ask because working with underlying data as an output may not work as desired.