The column with py27_0 is what build/version of python it is for. The column with defaults is to indicate which Anaconda channel it falls under. Different users or organizations can have their own channels but the default channel is defaults and another popular channel is conda-forge.
The way you install any specific version from that information is:
conda install pillow=4.2.1=py27h7cd2321_0
Which is of the format
conda install <package_name>=<version>=<build_string>
If you want to choose which channel (otherwise defaults is chosen by default):
conda install -c <channel> <package_name>=<version>=<build_string>