Use of pronoun in conditional passe

Question

I would like to know what the " l' " refers to in this sentence:   
Seriez-vous partis si je vous l'avais demandé? 
Would you have left if I had asked you?        
I can only surmise that it means something like: 
"Would you have left if I had asked it of you.  "

Accepted Answer

Bonjour Bob,
Excellent guess! You are correct: " l' " = it (= leaving)
I hope this is helpful.
Bonne journée !

Answer

As a follow up question, would it be acceptable to write it without "le"?Seriez-vous partis si je vous avais demandé.

Answer

Bonjour Bob,
You would include ' l' ' in the sentence as the verb 'demander' requires a direct object (transitive verb) being present. 
I hope this is useful.
Bonne journée !

Answer

Thank you, that was helpful. So I assume that any transitive verb would require a similar construction.

Answer

Yes, in principle. There are exceptions, though. Sometimes, even transitive verbs that normally require an object can be used without an object.

Il y a encore une chambre. Vous prenez? -- There is still one room. Do you take it?
Ce gâteau est délicieux. - Oui, j'aime! -- That cake is delicious. -- Yes, I like it!

In these cases, in a colloquial setting, if the object is unambiguous, one can leave it off in French (but not in English).