Our tenants are living there for six months.
This could mean that the tenants are living in the hous now, and:
either that the tenants have leased the house for a total of six months - the listener does not know how long they have occupied the house so far;
or that the tenants still have six months of the lease to run - the speaker could make this clear by adding 'another' or 'for the next' in front of 'six months'.
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