The position of M31N-1923-12c plotted by the AAVSO chart plotter
The recently discovered nova in M31, M31N 2012-01b, the second novae discovered in January 2012, turns out to be a re-erruption of M31N 1923-12c, a nova discovered by Edwin Hubble on December 11, 1923. More details here.
M31N 2012-01b 1s located at R.A. = 00h 42m 38.04s; Decl. = 41deg 08' 41.7", J2000, but I haven't been able to find brightness data yet.