Swedish rounding is the system traditionally used, which means you round UP when it is half way between. There is a more accurate system that requires you to round up half the time and round down half the time. However, using the swedish rounding,
1:15 equals 1.3
And for a semi-official view on the matter, the front of my Airservices Australia logbook says this:
mins = hours
0-2 = 0.0
3-8 = 0.1
9-14 = 0.2
15-20 = 0.3
21-26 = 0.4
27-32 = 0.5
33-38 = 0.6
39-44 = 0.7
45-50 = 0.8
51-56 = 0.9
57-60 = 1.0
As always, YMMV.