You can't start a workflow based on one column. You're going to have to do
the following (assuming "IndicatorColumn" is the name of the trigger field):

1) Create an extra column called "OldIndicatorColumn" (or something
similar).

2) When the workflow starts, if IndicatorColumn is equal to
OldIndicatorColumn, do nothing.

3) Otherwise, proceed with the workflow, and before it finishes, set
OldIndicatorColumn to the value of IndicatorColumn.

To do that you actually have to kick the workflow off whenever a change is
made and test in the workflow to see if the change is to the column you
want. If not, exit the workflow.