Answer
When a building is under lease, the economic benefits are obtained and controlled by the tenant (lessee) as the fruits of signing the lease contract (past event), and by this, the building may qualify as an asset of the tenant.
Work Step by Step
Under the definition, an asset has probable future economic advantages/benefits from being controlled or obtained by a particular past event or transaction. Thus, a leased building brings economic benefits to the tenant as the result of leasing the building (past event) and thus qualifies as an asset of the tenant.