Just to clarify the above comment in the context of using Python scripting in the Transform node to extract elements of date-type field, and to relate it back to the original question:
The presumption is that the input data field 'Original' is a date type field - hence it is not necessary to parse the input data using the strptime() function. The Tranform node automatically imports the datetime module so it is not necessary to include this in your script.
The following script extracts the month element (and the corresponding day and year elements) and outputs. Note that your Python script must handle Null values if there is a possibility that they may occur in the data (unlike when using the Calculate Fields node as described by Gerry - as the node provides defaults for Null date values).

The resultant output is:
