Most beam to column connections in practice are considered to be pinned by their designers regardless of whether or not the connection is to the side or top of the column or whether the material is wood or steel. That said, either connection type in wood or steel might be a rigid (moment) connection.
If this is new construction that you're designing, then you need to decide how you'd like the joint to be have and then detail the connection to be consistent with that.
If this is existing construction that you're evaluating, then you need to base your assessment on the type of connection detail used (stiffeners, welds, etc) and what you're able to ascertain of the original designer's intent as expressed in any of the design documentation that may be available to you.
We might be able to provide more definitive advice if you post a sketch of the detail that you're seeing or intend to use.