That would be Section 13a-11-59 of the Code of Alabama, which defines a demonstration as: (1) DEMONSTRATION. Demonstrating, picketing, speechmaking or marching, holding of vigils and all other like forms of conduct which involve the communication or expression of views or grievances engaged in by one or more persons, the conduct of which has the effect, intent or propensity to draw a crowd or onlookers. Such term shall not include casual use of property by visitors or tourists which does not have an intent or propensity to attract a crowd or onlookers.
Yes, this law is still very much in effect. Section (c) of that law restricts firearms within 1,000 feet of a demonstration: (c) It shall be unlawful for any person, other than a law enforcement officer as defined in subsection (a) of this section, to have in his or her possession or about his or her person or in any vehicle at a point within 1,000 feet of a demonstration at a public place, any firearm after having first been advised by a law enforcement officer that a demonstration was taking place at a public place and after having been ordered by such officer to remove himself or herself from the prescribed area until such time as he or she no longer was in possession of any firearm. This subsection shall not apply to any person in possession of or having on his or her person any firearm within a private dwelling or other private building or structure.
This, and other firearm laws may be found at http://alisondb.legislature.state.al.us/alison/codeofalabama/1975/coatoc.htm