Alternative for MC14543B
It's just a 4543 CMOS IC, different manufacturers use different prefixes. RCA (the founder, for what it's worth, although TI has this now) would call it CD4543B. SGS / ST use 'HEF'. Motorola/On semi use MC(1), as in this case. Other manufacturers use different names yet.

On ebay or digikey or.. wherever, just search for '4543'.

For what it's worth though, 4543 is designed for LCDs and has piddly little output current. CD4511 is better for driving LEDs, as it can sink 25mA instead of.. a couple.