switch/case not recognizing certain char inputs - c

Question

I am creating a program for an online coding course which takes a poker hand and calculates the odds of the hand winning. I am currently in the early stages, writing the functions necessary to advance to the next part of the assignment. I have isolated my issues to one function, card_from_letters.
I created my-test-main.c to test card_from_letters. It creates two chars, representing the suit and value of a poker card. It then creates the struct testCard2.
A card_t struct has two components: an unsigned int for value, and an enumerated type for suit between SPADES and CLUBS. I cannot change the struct card_t.
int main(void) {
char sui = 'c';
char val = 'Q';
card_t testCard2 = card_from_letters(val, sui);
printf("last test! My card %c%c is value %d, and suit %d!\n", val, sui, testCard2.value, testCard2.suit);
}
This is my function card_from_letters:
card_t card_from_letters(char value_let, char suit_let) {
card_t temp;
assert(suit_let == 'd' ||'h' || 'c' || 's');
assert((value_let >= '2' && value_let <= '9') || (value_let = '0' || 'K' || 'Q' || 'J' || 'A'));
switch (value_let) {
case '2': temp.value = 2; break;
case '3': temp.value = 3; break;
case '4': temp.value = 4; break;
case '5': temp.value = 5; break;
case '6': temp.value = 6; break;
case '7': temp.value = 7; break;
case '8': temp.value = 8; break;
case '9': temp.value = 9; break;
case '0': temp.value = 10; break;
case 'K': temp.value = 13; break;
case 'Q': temp.value = 12; break;
case 'J': temp.value = 11; break;
case 'A': temp.value = 14; break;
}
switch (suit_let) {
case 's': temp.suit = SPADES; break;
case 'h': temp.suit = HEARTS; break;
case 'd': temp.suit = DIAMONDS; break;
case 'c': temp.suit = CLUBS; break;
}
return temp;
}
When val is set between '2' and '9', I am able to run card_from_letters with no problem. When I run my-test-main.c as it is here through gdb, the execution arrow makes it to switch (value_let), but then skips all cases and enters switch (suit_let), where it returns the correct suit. What am I missing here? How come card_from_letters works for chars 2 to 9, but not 0 to A?