Length function into oracle and sql

Hi
I have a simple problem into my database I use length function that determines length of string into sql and oracle both.
now I pass my data from sql to oracle so into sql I check the length of charecters same I will do into oracle also
but when my string has some Unicode charecters the length of that charecters are shown differently into the oracle and sql

into sql

select Len('⻩');   

ans=1

into oracle

SELECT LENGTH('⻩'') "Length in characters"
   FROM DUAL;

ans=3

how can I remove inconsistency ?

how can I make same ans into sql because I have control over sql and does not have control over oracle database