The logical operator OR is supported for use in conditional expressions, connecting either comparison operators or logical predicates. When dragging an Or operator into a variable, the following tree element is created.
Variable Creation > Input > Variables: SQL Elements pane - Logical > Or
Columns and/or other expressions can be moved into the (empty) branches of the tree, where the first argument is to the left of the OR, the second to the right.
There are no special properties for the Or operator.