I’ll go for old round table. Round old table to me sounds odd because it suggests that you and the table are old mates as in expressions like: You silly old thing/You dear old chap - in other words old is being used in an affectionate way. The rough guide for order is that the evaluative one comes before the descriptive one. So in your example: What sort of table is it? Answer it’s old. What does it look like? Answer it’s round.
“Professor English Grammar” is a famous grammar book in Pakistan like Michael Swan’s Practical English Usage. It consists of almost 50 pages, and each page shows a new grammar rule.