You can also use normal paragraph numbering: just select the cells in that column and press the "Numbering On/Off" button on the toolbar.
You probably don't want the indent that comes with the default numbering; just put the cursor in the first numbered cell and press Shift+Tab.
If you want plain numbers, with no extra punctuation, click on the Bullets & Numbering button, then the "Options" tab and remove everything from the "Before" and "After" fields, then, on the "Position" tab, change "Numbering followed by" to "Nothing".
PS: I don't see any big advantage/disadvantage in either of these approaches. Either one should work fine.
AOO 4 • Linux • Fedora 17