Use modern, as you always should be. Use the Get Text activity, indicate the value as your target and ICMS-DIF as your anchor. If it can be other values after the dash, ie ICMS-XXX, then after indicating that anchor change the value in the anchor selector to ICMS-*
Another thing you can do is use UI Explorer to look at that value and see if there are any properties like rowname=“ICMS-DIF” that you could use to identify it.