I don't understand Bengali at all, but the character ৎ does have it's own Unicode codepoint (U+09CE, BENGALI LETTER KHANDA TA). It was introduced in Unicode 4.1 in 2005.
> Until 2005, Unicode did not have one of the characters in the Bengali word for “suddenly”.
The codepoint does exist now, but it took ten years before it was included.
(though I agree with most of it)