ADJUST TDS AGAINST TAX DEMAND

Yes.In the past few years the CPC used to do the online adjustment for the past demand against latest year tax refund.

But now a days it depends on case to case.

So better file ITR for AY-2019-20 if filed wait for tax refund and pay the demat for 2013-14 AY & 14-15 AY

You can paid the demand and file for refund

But if you are not agreed for past demand then you may submit disagree response

Sec 143 1A arises in the following cases:
a)A communication of proposed adjustment under Sec 143(1) (a) is sent to taxpayers wherein there is a mismatch of the income /deductions/exemptions reported in Income tax return.
you find where there is a mismatch.
there can be no adjustment of tax paid of one year against another year liability.

So better to clear off the past demand . Demand setoff makes your profile red due to violation in earlier years